Prostaglandin synthetase can be defined as a enzyme complex which catalyzes the oxidative cyclization of unsaturated C-20 fatty acids, e.g., arachidonic acid, into prostaglandins in the presence of a suitable coenzyme.
In 1937, the name "prostaglandin" was coined to describe the pharmacologically active components of seminal fluid. In 1964, the enzymatic conversion of C-20 fatty acids into prostaglandins (hereinafter PGs) was demonstrated simultaneously by two groups of workers led by Van Dorp in Holland and Bergstrom in Sweden [See Biochim. Biophys. Acta 90, 204 and 207 (1964)].
The high degree of interest in PG studies has been prompted by the ubiquity, high potency and varied biological activities of the compounds. Their presence in most tissues and cells of animals has led to investigations into a wide range of therapeutic applications, such as the role of PGs in abortion, nasal congestion, stomach ulcers, asthma, hypertension and inflammation.
It is now generally recognized that PGs play a major role in the inflammatory process and in the generation of inflammatory pain. In 1971, aspirin-like drugs were shown to inhibit PG release from human platelets, to inhibit PG release from perfused dog spleen and to inhibit PG synthesis in guinea pig lung. Inhibition of PG release by aspirin, salicylic acid, indomethacin, and other aspirin-like drugs, has now been demonstrated in some 30 different tissue systems.
The PG synthetase enzymes which are responsible for synthesizing PGs appear to be present in every mammalian tissue so far investigated, although the activity in each tissue varies greatly. In mammalian tissues, the only tissues which have been found to possess high activity are sheep and bovine seminal vesicles (BSV). Because of the high activity, the majority of biosynthetic studies involving conversion of fatty acids into PGs have been conducted using sheep and bovine seminal vesicles as the enzyme source.